From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LDMBy-0006W8-B0 for qemu-devel@nongnu.org; Thu, 18 Dec 2008 11:57:42 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LDMBt-0006U0-KF for qemu-devel@nongnu.org; Thu, 18 Dec 2008 11:57:41 -0500 Received: from [199.232.76.173] (port=50029 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LDMBt-0006Tu-9G for qemu-devel@nongnu.org; Thu, 18 Dec 2008 11:57:37 -0500 Received: from gecko.sbs.de ([194.138.37.40]:22760) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LDMBs-0007xO-NG for qemu-devel@nongnu.org; Thu, 18 Dec 2008 11:57:37 -0500 Message-ID: <494A80DE.6020601@siemens.com> Date: Thu, 18 Dec 2008 17:57:02 +0100 From: Jan Kiszka MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH] x86: Manage BIOS boot menu via command line References: <494A4A55.2090700@siemens.com> <200812181620.01572.paul@codesourcery.com> <494A7A46.7040300@codemonkey.ws> In-Reply-To: <494A7A46.7040300@codemonkey.ws> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: qemu-devel@nongnu.org Anthony Liguori wrote: > Paul Brook wrote: >> On Thursday 18 December 2008, Jan Kiszka wrote: >> >>> When booting a guest from the command line, you normally do not need the >>> interactive boot menu with its 3 s waiting that someone might press F12. >>> So this patch introduces a mechanism to enable the boot menu only on >>> demand, ie. when the user provided the command line switch -bootmenu. >>> This reduces boot times to their original dimension. >>> >>> The host-guest interface used here is CMOS RAM byte 0x60. If it is >>> non-zero, the guest BIOS will skip the F12 delay, keeping the previous >>> behavior in case the host does not support it. -bootmenu was chosen in >>> favor of -boot as the syntax of the latter is not easily and cleanly >>> extensible. >>> >> >> I'm not sure I believe this. We already support multiple options to >> -boot so why not just add another one (e.g. "q") that means include >> the boot menu? >> i.e. -boot qcad would give the current behaviour. >> > > Or -boot cad,prompt=[on|off] -boot currently takes arbitrary characters from a-z. Adding some extension means changing a lot of code (the users are unfortunately not well structured right now). And how to deal with the monitor interface then? Keep it, extend it? Moreover, how should we express the case of enabling the boot menu without providing any boot device, "-boot prompt=on"? Then parsing this will be fun - not impossible, for sure. But so far I'm looking for a straightforward approach. > >> I've no particular preference whether this is communicated to the bios >> via the current 0x3d region or via a new byte. It looks like there's a >> spare bit in byte 0x38 that could be used. >> There are even more bits left in this byte. If CMOS is the final way to go, I will switch to this. > > Or firmware config since that can be shared with non-x86 targets. I'm open for the firmware config if you explain to me how state information is supposed to be transfered from rombios32.c (where the fw_cfg is evaluated) to some function in rombios.c. Tried this but found nothing obvious. Jan -- Siemens AG, Corporate Technology, CT SE 26 Corporate Competence Center Embedded Linux